phosgene
noun /ˈfɒzdʒiːn/
/ˈfɑːzdʒiːn/
[uncountable]- a poisonous gas that was used as a chemical weapon during the First World WarWord Originearly 19th cent.: from Greek phōs ‘light’ + -gen, with reference to its original production by the action of sunlight on chlorine and carbon monoxide.